The research activities of the Arthritis Section at Boston University School of Medicine are directed to two major areas (1) the chemistry, ultrastructure and immunologic properties of amyloid and (2) the development and functional capacity of normal and pathologic synovial membrane. These studies are conducted by several investigators and rely on their backgrounds and expertise in various disciplines including protein chemistry, immunology, experimental pathology, tissue culture and electron microscopy. A team approach is utilized for most problems and has been particularly effective in correlating primary structure, immunological variation and molecular interactions of the various constituents in human amyloid deposits. Studies on the pathogenesis of acute and chronic joint disease rely mainly on electron microscopic, biochemical and functional studies of synovial cells in vivo and in vitro. Our goal is to determine if there is fine structural evidence of viral infection, abnormal function (such as phagocytosis and/or macromolecular synthesis) or chromosomal abnormalities in the host tissues.